Light emitters are known per se and are used in every realm of daily life. They are, inter alia, used in general illumination systems, for example, for illuminating indoor and/or outdoor environments, homes, shops, factories and offices, but also, for example, in vehicles of any kind. Also in different application areas, such as in image projection systems, light emitters are often used. Beamers, projection televisions and liquid crystal display devices all have some kind of light source to illuminate the image generated by the device.
Due to this broad span of application areas in which light emitters are used, many different light emitters exist. Incandescent light sources and high and low pressure gas discharge lamps, compact fluorescent lamps, halogen lamps together with the relatively novel semiconducting light emitters such as light emitting diodes and organic light emitting diodes. A common drawback of all of these light emitters is that they produce heat which in general is not wanted.
In recent years semiconducting light emitters have become more and more popular due to the relatively small dimensions of the light emitters in combination with a relatively high light emission intensity. Furthermore, the efficiency and the operational life-time of the semiconducting light emitters are substantially higher compared to any of the other light emitters, which is preferred for environmental and cost reasons. However, the light output that can be generated by the light emitting diode is directly related to the amount of cooling of the light emitting diode. For high-power applications, cooling is obtained via a heat sink comprising cooling fins along which air flows for cooling the high-power light emitting diodes. So, although the semiconducting light emitters have relatively small dimensions, the use of elaborate cooling arrangements may generate a relatively bulky light source, which is not preferred.
In addition, for many applications, a flexible illumination system is required in which the light source or light sources may be moved to different locations within a room relatively easily. For this reason, tracks or rail systems comprising a light source or a plurality of light sources have been applied in which the light source(s) may be positioned at will at any location along the track or rail. Such a system is, for example, introduced to the market by a company known as “Lightolier®” (see their web site www.lightolier.com). Especially their “LED Magnetic Track Undercabinet Fixture” provides a plurality of LED light sources magnetically attached to a track to allow easy repositioning of the LED light sources along the track. Although the LED light sources may be relatively easily repositioned, the light sources cannot be directed and still are relatively bulky due to the cooling fins required.
Thus, a disadvantage of the known illumination system is that the light sources still are relatively bulky and that the direction of light emission cannot be altered.